Drip irrigation (sometimes called trickle irrigation) is an effective way to conserve water. It works by applying water slowly, directly to the soil. The high efficiency of drip irrigation results from two primary factors. The first is that the water soaks into the soil before it can evaporate or run off. The second is that water is only applied where it is needed. While drip systems are simple and pretty forgiving of errors in design and installation, there are some guidelines that if followed, will make for a much better drip system.

The Basic Parts of a Drip SystemValve - Use any valve you want! They

can be automatic or manual. If you use an anti-siphon valve it has a built-in backflow preventer which saves money!

Backflow Preventer - You need to use a backflow preventer on ALL drip systems. No exceptions! Your landscape has all kinds of nasty things in it that will make you sick or worse if you drink them. Thus irrigation water is considered a contaminant (creates a

health hazard) rather than just a pollutant.Pressure Regulator - Most drip systems

will need a pressure regulator. Follow the manufacturers recommendations regarding pressure. The regulator can go before or after the valve. Traditionally it is installed after the valve.

Filter - You must use a filter. Drip emitters have very small openings that are easily clogged. Municipal water is not free from particles that will clog your emitters! Use a 150 mesh screen or one with a higher mesh number like 200 mesh. The inexpensive plastic

filters often sold for drip systems should be installed after the pressure regulator. However, a top quality filter installed right at the water source protects the valves and the pressure regulator too. Most valve failures result from sand or rust particles clogging of the tiny passages inside the valve! Use a filter that is the same size as, or larger than, the valve.

Emitters - Most emitters emit about one gallon per hour (gph). A low flow rate such

ValveBackflow PreventerPressure RegulatorFilterTubing Adapter

Drip Tubing

18” MinimumBetween Emitters

Emitters

End Cap

Drip for a Waterwise Landscape April/May Events

Think a BrighT green FuTure - earTh Day Join in the celebration

and numerous activi-ties Saturday, April 21st from 10 AM - 2 PM at the Pajarito Environ-

mental Education Center (PEEC) located at

3540 Orange Street Los Alamos, NM(505) 662-0460

DaviD Salman DiScuSSeS

rock garDening (growing in TuFF )David Salman with

Santa Fe Green House will discuss how to suc-cessfully grow plants in

tuff or volcanic ash depos-its Thursday, May 17th, 7 PM at Fuller Lodge

2132 Central Los Alamos, NM (505) 662-2656

Spring has arrived in Los Alamos once again. That time of year when all of us begin planning our gardens with anticipation. The Los Alamos Cooperative Extension Service and the Department of Public Utilities want to remind you that a beautiful, colorful landscape can be waterwise and reduce summer water bills. In conjunction with the full-color wall calendar delivered to you in January we are including with your utility bill a series of newsletters - Waterwise Gardening - between April and September. The newsletters will focus on various ways you can conserve water in your landscaping.

We hope that the information contained in these newsletters is helpful. Contact us with questions or suggestions. We’d love to hear from you.

Carlos Valdez, County Program DirectorCooperative Extension Service(505) 662-2656 http://www.l o s a l a m o s e x t e n s i o n . n m s u . e d u

Department of Public Utilities, Los Alamos County (505) 662-8130 http://www.losalamosnm.us

Welcome

This IssueDrip for a Waterwise Landscape

The Basic Parts of a Drip SystemOften Asked Questions

Plant of the Month

Drought Outlook

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APRIL 2007 WG-0407-JWH

Photo: Robert Villegas, CanyonEcho Graphics, Los Alamos, NM 2006

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as 0.6 gph, often referred to as “1/2 gallon per hour” emitters is preferable. Use pressure compensating emitters if you are irrigating a hilly area. There are many different types and brands available. Use single outlet emitters for a less troublesome drip system

Mainline - The mainline is the pipe that goes from the water source to the valves. The mainline may be made of galvanized steel, copper, SCH 40 PVC, SCH 80 PVC, Cl 315 PVC, Heavy Wall Polyethylene (SDR 7 or SDR 9).

Drip Tubing - Drip tubing is a thin wall polyethylene tube, and is generally produced in metric sizes. Common sizes are 12 mm (0.455” or 3/8”), 16mm (0.620” or 1/2”), 18mm (0.720” or 1/2”), and 24mm (0.940” or 3/4”). Do you see the problem? Two sizes are commonly referred to as “1/2 inch” in the USA! The fittings for these two are not interchangeable. So make sure you know what you’re getting when you buy it! Do not bury drip tubing underground- gophers love to chew buried tubing!

Adapters and fittings - Used to attach the drip tube to the other parts. Important- make sure the fittings are the exact right size! Using fittings made for a different tubing size will result in the tube blowing out of the fitting. 9 times out of 10, when a tube blows out of a fitting it is because the fitting is the wrong size.

End Cap- The end cap is important. Without it the water all runs out the end of the drip tube.

Often Asked QuestionsHow Many Emitters are Needed?Two emitters per plant, minimum. Trees and large shrubs will

need more. Obviously, using two allows for a backup if one clogs up (which happens even on the best designed and maintained drip systems.) But just as important, more emitters also wet more soil area. This results in more roots, and a healthier, happier plant. Exception: if the plants are very close together you may need to use less than two per plant in order to maintain the minimum spacing between emitters. Minimum spacing for emitters: Rule of thumb- install emitters 45 cm (18”) apart under 80% of the leaf canopy of the plant. This is where the majority of the water absorbing roots are.

What valve size to use?Use a 3/4” valve for most systems. Any type of valve may be

used.

How many emitters per valve?Use the chart below to determine how many emitters at the

standard 18” spacing can be installed on each valve circuit.

What is the maximum allowable tube length?The length of drip hose depends on emitter spacing. With the

standard 18” spacing, you should not exceed 200’ from the point the water enters the tube to the end of the tube. Thus you could have 400’ of tube if the water entered the tube in the middle. You can extend one tube off of another as long as the total length of the tubes that are connected is not more than 200’.

Should I bury emitters?Generally emitters are not buried. There are select

applications, such as subsurface drip irrigation for turf, where emitters are buried. Tubing is generally placed on top of the soil surface with mulch on top.

What about feeder tubes, spaghetti, and distribution tubing?Feeder tubes, “spaghetti,” and distribution tubing are all

names used for small diameter tubes, that is anything less than 3/8” in diameter. Maintenance is a problem as these small tubes tend to be easily cut, broken, pulled loose, and are generally a nuisance. The exception is when they are stapled above ground to a trellis or arbor for watering hanging plants. They need to be firmly attached, in a location where they will not be damaged.

Are fittings interchangeable?There are many sizes of drip tubing sold, and the fittings have

to be made for the exact size tube you are using. If they don’t fit exactly, they will either be very hard to install, or the tube will blow off the fitting. Sometimes it takes a week or so for the tube to come loose, but if the fitting is even a little too large, the tubing will come off eventually.

There are two types of fittings. The first and most commonly used is the “compression” type. On this type the tubing shoves inside the fitting. Compression type fittings tend to be harder to install, but hold up longer. The second type is “barbed” fittings. With barbed fittings you shove the tubing over a barb on the fitting. This stretches and weakens the thin wall of the drip tubing as it goes over the barb. Problems arise over time, usually within a few years, as the tubing splits and the fittings comes off.

Maximum 200 feet of tubingEmitter volume

(gallons per hour)No. of emitters for 3/4” water supply

No. of emitters for 1” water supply

1/2 gph 300 700 1 gph 180 420

New Mexico State University is an equal opportunity, affirmative action employer and educator. NMSU, the U.S. Department of Agriculture and Los Alamos County cooperating.

Desert Beardtoungue (Penstemon pseudospectabilis)

36” x 18” wide, (seed propagated). A beautiful, nearly ever-blooming species native to southern New Mexico. The long spikes of hot pink flowers contrast beautifully with the large gray leaves. A few deep waterings during the heat of the summer are all that is required to keep the plant blooming. This Penstemon loves hot weather, prefers well drained soil, and is recommended for both White Rock and Los Alamos.

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Drought ongoing, some improvement

Drought likely to improve, impacts ease

Drought to persist or intensify

Drought development likely

Seasonal Drought OutlookTaken from the National Oceanic & Atmospheric Administration’s Climate Prediction Center online at: http://www.cpc.noaa.gov/products/expert_assessment/seasonal_drought.html

Depicts general, large-scale trends based on subjectively derived probabilities guided by numerous indicators, including short- and long-range statistical and dynamical forecasts. Short-term events -- such as individual storms -- cannot be accurately forecast more than a few days in advance, so use caution if using this outlook for applications -- such as crops -- that can be affected by such events. “Ongoing” drought areas are approximated from the Drought Monitor (D1 to D4). For weekly drought updates, see the latest Drought Monitor map and text. NOTE: the green improvement areas imply at least a 1-category improvement in the Drought Monitor intensity levels, but do not necessarily imply drought elimination.

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